A value in milliseconds that controls how long the
master waits on a commit for acknowledgment from a slave
before timing out and reverting to asynchronous
replication. The default value is 10000 (10 seconds).

Whether semisynchronous replication currently is
operational on the master. The value is 1 if the plugin
has been enabled and a commit acknowledgment has not
occurred. It is 0 if the plugin is not enabled or the
master has fallen back to asynchronous replication due
to commit acknowledgment timeout.